<template>
    <div class="pagination">
        <button :disabled="pageNo==1" @click="$emit('getpageNo',pageNo-1)">上一页</button>
      <button v-if="startNumAndEndNum.start>1" @click="$emit('getpageNo',1)" :class="{active:pageNo==1}">1</button>
      <button v-if="startNumAndEndNum.start>2">···</button>
      <button v-for="(page,index) in startNumAndEndNum.end" :key="index" v-show="page>=startNumAndEndNum.start" @click="$emit('getpageNo',page)" :class="{active:page==pageNo}">{{page}}</button>
      <button v-if="startNumAndEndNum.end<totalpage-1">···</button>
      <button v-if="startNumAndEndNum.end<totalpage" @click="$emit('getpageNo',totalpage)" :class="{active:pageNo==totalpage}">{{totalpage}}</button>
      <button :disabled="totalpage==pageNo" @click="$emit('getpageNo',pageNo+1)">下一页</button>
      
      <button style="margin-left: 30px">共 {{total}} 条</button>
    </div>
  </template>
  
  <script>
    export default {
      name: "Pagination",
      props:['pageNo','pageSize','total','continus'],
      computed:{
        totalpage(){
            return Math.ceil(this.total/this.pageSize)
        },
        startNumAndEndNum(){
            const {continus,pageNo,totalpage}=this;
            let start = 0
            let end = 0
            if(continus>=totalpage){
                start=1;
                end=totalpage
            }else{
                start=pageNo - parseInt(continus / 2);
                end= pageNo + parseInt(continus / 2);
                if(start<1){
                    start=1;
                    end=continus;
                }
                if(end >totalpage){
                    end=totalpage;
                    start = totalpage - continus + 1;
                }
            }
            //        27  28  29 30 31
            return{start,end}
        }
      },
    }
  </script>
  
  <style lang="less" scoped>
    .pagination {
    text-align: center;
      button {
        margin: 0 5px;
        background-color: #f4f4f5;
        color: #606266;
        outline: none;
        border-radius: 2px;
        padding: 0 4px;
        vertical-align: top;
        display: inline-block;
        font-size: 13px;
        min-width: 35.5px;
        height: 28px;
        line-height: 28px;
        cursor: pointer;
        box-sizing: border-box;
        text-align: center;
        border: 0;
  
        &[disabled] {
          color: #c0c4cc;
          cursor: not-allowed;
        }
  
        &.active {
          cursor: not-allowed;
          background-color: #409eff;
          color: #fff;
        }
      }
    }
  </style>
